Osteosarcoma is a bone cancer that starts in the bone-forming cells. Osteo means bone and sarcoma is a cancer that starts in the connective or supporting tissues, for example: muscle, bone, fat, cartilage, or blood vessels.
This type is the most common type of bone cancer. It develops in growing bones and therefore it occurs more often in children and young adults, although it develops in older adults, too. Osteosarcoma often develops in the long bones of the arms and legs, but it can develop in any other bone.
There are several types of osteosarcoma: chondroblastic (in cartilage cells), parosteal, periosteal, telangiectatic, and small cell. Most of these types are high-grade cancer, implying that the tumour is aggressive and can invade the surrounding tissues or organs. It typically spreads to the lungs.
The usual symptoms of osteosarcoma are:
- pain in the area around the tumour
- swelling, tenderness if the tumour is in the joints area
- weakened bone, due to the tumour, when the cancer is usually found
- reduced movement because the joint may feel stiff
The symptoms will vary from mild to severe, and therefore it may take months until osteosarcoma is diagnosed. In some cases, symptoms may appear suddenly.
The cause of osteosarcoma in young people is unknown. It is associated to growth, although in rare cases it can be inherited.
The cause of osteosarcoma in adults can be other condition such as Paget’s disease or previous radiotherapy.
The risk factors of osteosarcoma are:
- age – common between 10 and 24
- height – those with osteosarcoma are taller than the average height for their age
- inherited retinoblastoma (eye cancer in children)
- gender – higher incidence in males
- Paget’s disease
- Previous radiotherapy
- Children with Li-Fraumeni syndrome (rare disorder of the p53 gene), brain cancer, breast cancer, leukemia, and adrenal cancer
- Children with Werner syndrome (a very rare disorder that may involve the WRN gene)
- People with Rothmund-Thomson syndrome (an uncommon disorder characterized by short height, rash, hair loss, and skeletal dysplasia)
The treatment of osteosarcoma includes:
- Surgery – removing the cancer up to a healthy part of the bone or the joint, and replacement (prosthesis) of the removed bone; in certain cases, amputation is necessary, when the cancer has spread into the nerves and the surrounding blood vessels
- Chemotherapy – cytotoxic drugs used to kill cancer cells; chemotherapy may be administered before surgery, too with an aim to shrink tumours and possibly avoid amputation; chemotherapy may be reinforced by other medicines to prevent recurrence
- Radiotherapy – high-energy x-rays to kill cancer cells; it can be used
In some cases, treatment can give side effects, even years after: function of the heart or kidneys, or increased risk of another type of cancer.